Obama wins Twitter

It's official: the Obama campaign tweet hailing victory on election night won the year on Twitter. It also won the most re-tweeted in history.

Twitter unveiled a look back at 2012 on Tuesday, recounting memorable events and tweets on the social networking site. The Obama campaign's election night tweet, "Four more years," which included a picture of the first couple hugging, bested Justin Bieber and NFL player TJ Lang for the record.

"Within hours, this Tweet simultaneously became the most retweeted of 2012 — and the most retweeted ever, sent by people in more than 200 countries around the world," Twitter said in its lookback.

Besides the U.S. presidential election, other notable events that generated the most twittering were the Olympics, the MTV Video Music Awards, and the Super Bowl.